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Abstract
Abstract
Results from previous studies are ambiguous regarding the relationship between long working hours and sick leave, and there are obvious methodological shortcomings in many of the previous conducted studies. The aim of this study was to investigate the effects of long working hours (≥12 hour shifts) on later sick leave using objective records of shift work exposure and of short and long term sick leave.
A total of 1,538 nurses (mean age: 42.5, SD : 12.0; response rate 42.5%) participated. Payroll and archival sick leave data over a four-year period were retrieved from employers' records and aggregated over every third calendar month. A multilevel negative binomial model was used to investigate the effects of exposure to long working hours, on subsequent sick leave rates the following three months. Covariates included prior sick leave, number of shifts worked, night and evening shifts, personality (morningness, flexibility, and languidity), and demographic characteristics.
Exposure to long working hours reduced the risk of sick leave the subsequent three months [adjusted model, incidence rate ratio (IRR)=0.946, 95%CI=0.919-0.973, p <0.001]. Night shifts were unrelated to sick leave, whereas evening shifts significantly increased the risk of sick leave in the subsequent three months [adjusted model, IRR=1.009, 95%CI=1.002-1.016, p =0.012].
Long working hours emerged as a protective factor against future sick leave. The restorative effects of extra days off with long working hours, 'the healthy shift worker effect', and a higher degree of presenteeism may be possible explanations to these findings.
The study was partly funded from Nordforsk, Nordic Program on Health and Welfare (74809).